System Administrator

Core Responsibilities

• Administer Windows Server, Active Directory, Group Policy, DNS, DHCP, permissions, and routine identity lifecycle tasks.
• Manage VMware vSphere/ESXi, Linux servers, virtual machines, storage, patching, backups, certificates, logs, and service troubleshooting.
• Configure and support pfSense, OpenVPN, Cisco and UniFi switching, VLANs, routing, NAT, firewall policy, wireless, and network segmentation.
• Administer the primary Microsoft 365 tenant and smaller tenants, including Entra ID, Exchange Online, Teams, SharePoint, licensing, MFA, and Conditional Access.
• Triage and investigate Microsoft Defender XDR and Sentinel alerts; collect evidence, contain, remediate, document, or escalate incidents.
• Manage and security-monitor the CUI environment, including access control, logging, vulnerability remediation, configuration management, and compliance evidence.
• Provide onsite helpdesk support, workstation deployment, onboarding/offboarding, cabling, hardware replacement, and equipment inventory.
• Support GitLab and development infrastructure, including access, availability, backups, certificates, and basic service troubleshooting.

Required Qualifications

• 3+ years of hands-on systems administration or advanced infrastructure support experience in production environments.
• Strong TCP/IP, DNS, DHCP, subnetting, routing, VLAN, NAT, VPN, firewall, Windows/AD, Linux, and virtualization fundamentals.
• Experience administering Microsoft 365; Microsoft security operations experience is strongly preferred.
• Demonstrated ability to troubleshoot independently, document changes, validate results, and use safe rollback procedures.
• Ability to work onsite, perform physical IT support, and handle CUI and sensitive information under applicable requirements.

Preferred Experience

• Direct experience with pfSense, OpenVPN, Cisco, UniFi, VMware vSphere, and GitLab.
• Experience with Microsoft Entra ID, Conditional Access, Intune, Exchange Online, Defender XDR, Sentinel, and KQL.
• Experience supporting segmented, regulated, government-contractor, defense-industry, or other security-sensitive environments.
• Working knowledge of CUI, CMMC Level 2, NIST SP 800-171, DFARS 252.204-7012, access-control evidence, and compliance documentation.
• Experience maintaining system security plans, configuration baselines, inventories, diagrams, remediation records, and audit evidence.
• PowerShell, Bash, Python, or other scripting and automation experience.
• Relevant certifications such as Security+, Network+, CCNA, Microsoft, VMware, or Linux certifications, or equivalent demonstrated experience.